9i Buda Limestone, Whitney 



The interambulacral areas are widest at the apical disk, 

 and gradually decrease in size to the peristome. They are com- 

 posed of 6-7 plates ornamented with mammillated, noncrenulated, 

 imperforate tubercles which increase in size to the ambitus, 

 decreasing again toward the peristome. Besides these primary 

 tubercles, there are granules distributed about their bases and 

 over the surface of the plates, but the specimens studied are 

 not well enough preserved to make out their distribution. 



The peristome is large, about .61 of the diameter of the test, 

 decagonal and notched. The ambulacral and interambulacral 

 lips are nearly equal and bilobate. 



The apical system is prominent and elevated above the general 

 surface of the test. It consists of five genital and five ocular 

 plates. The genital plates are variable in form, the anterior 

 plates being larger than the posterior plates. They are polygonal 

 in outline and bounded by six or seven sides. The oculars are 

 likewise somewhat variable in form and size. They are bounded 

 by three long and two short sides. The surface of each genital 

 plate is ornamented with a central depression containing a mame- 

 lon from which ridges radiate outward to the edges of the plate. 

 The genital openings are at the edges of the plates where they join 

 the corona. The periproct is subquadrangular and bordered by 

 a raised collarette. 



The specimens collected range in size from 4.5 mm. to about 

 9 mm. in diameier. They are not well preserved except in the 

 smaller sizes. They occur most frequently at the base of the upper 

 division of the Buda Limestone, but they range to the top and 

 occur at the contact with the Eagle Ford. None has appeared 

 yet in the lower division of the Buda, nor in the other divisions 

 of the Washita series. 



This species does not closely resemble any other described 

 form of Goniopygus. 



Number of specimens: 16. 



Occurrence: Upper division of Buda Limestone, Austin, 

 Texas. 



CENTRECHINIDM 

 Genus Codtopsis, Agassiz 

 Codiopsis texana, n. sp. 

 Plate III, figures 1-4; Plate VI, figure 2 



